The present invention relates to a switch apparatus for use in vehicles.
To achieve high operation stability during driving of an automobile, it is preferable that the driver always looks in the travel direction of the automobile. In view of this, switch apparatuses for vehicles that are touch-operated have been proposed (refer, for example, to Japanese Laid-Open Patent Publication Nos. 2004-149086, 2003-143741, 2003-118416, 2002-166832, and 2002-50801). Such a switch apparatus enables the driver to feel for the desired switch. However, when the driver is not familiar with the characteristics of a switch apparatus that he or she operates, or when the driver operates a switch that he or she uses infrequently, the driver may not be confident of touch-operation. When operating a switch in such a case, the driver visually checks the position of the switch. Thus, it is preferable that switches are positioned relatively close to the driver's line of eye sight during driving to improve operability. For example, switches may be arranged on the periphery of the steering wheel. This enables the driver to operate many kinds of switches, arranged on the periphery of the steering wheel, while driving the automobile without greatly moving the driver's line of eye sight.
As an apparatus including switches other than the vehicle switches, UK Patent No. 2344905 discloses a personal digital assistance (PDA) including switches on its rear side. The PDA includes a touch screen (switches) on its rear side and a transparent screen display on its front side. The transparent screen display enables the touch screen to be viewed from the front side of the PDA.
On the periphery of the steering wheel, combination switches are arranged at the left and right sides of the steering column. A space for expansion of an air bag must be provided in front of the steering wheel. Thus, the periphery of the steering wheel has limited space for arranging additional switches. An additional switch may be arranged on the rear side of the steering wheel or of the combination switches. Such locations are blind spots for the driver. In such cases, the driver is able to easily operate the switches but is not able to visually check the position of the switches. This does not improve the operation reliability of the switches, or ensure the operating of the switches. Thus, locations for the switches are limited.
The structure of the apparatus disclosed in UK patent No. 2344905 may be applied to the vehicle switch apparatus. However, the disclosed apparatus uses a touch screen and a screen display, which results in relatively high costs.